A modern pregnancy test

A pregnancy test attempts to determine whether or not a female is pregnant. Pregnancy ( Latin graviditas) is the carrying of one or more offspring known as a Fetus or Embryo, inside the Uterus of a Female Records of attempts at pregnancy testing have been found as far back as the ancient Greek and ancient Egyptian cultures. The term ancient Greece refers to the period of Greek history lasting from the Greek Dark Ages ca Ancient Egypt was an Ancient Civilization in eastern North Africa, concentrated along the lower reaches of the Nile River in what is now Modern pregnancy tests look for chemical markers associated with pregnancy. These markers are found in urine and blood, and pregnancy tests require sampling one of these substances. The first of these markers to be discovered, human chorionic gonadotropin (hCG), was discovered in 1930 to be produced by the placenta. Human chorionic gonadotropin ( hCG) is a Glycoprotein Hormone produced in Pregnancy that is made by the Embryo soon after conception While hCG is a reliable marker of pregnancy, it cannot be detected until after implantation: this results in false negatives if the test is performed during the very early stages of pregnancy. Obstetric ultrasonography may also be used to detect pregnancy. Obstetric sonography (ultrasonography is the application of Medical ultrasonography to Obstetrics, in which ultrasound is used to visualize the Embryo Obstetric ultrasonography was first practiced in the 1960s; the first home test kit for hCG was released in the mid-1970s.

History

Jan Steen's The Doctor's Visit. Jan Havickszoon Steen (c 1626 – buried February 3 1679) was a Dutch genre painter of the 17th century (also known as the Dutch Included in this 17th century painting is a depiction of a dubious pregnancy test: a ribbon dipped in the patient's urine and then burned. ^[1]

The ancient Egyptians watered bags of wheat and barley with the urine of a possibly pregnant woman. Germination indicated pregnancy. The type of grain that sprouted was taken as an indicator of the fetus's sex. Hippocrates suggested that a woman who had missed her period should drink a solution of honey in water at bedtime: resulting abdominal distention and cramps would indicate the presence of a pregnancy. Hippocrates of Cos II or Hippokrates of Kos ( ca. 460 BC – ca Avicenna and many physicians after him in the Middle Ages performed uroscopy, a nonscientific method to evaluate urine. TemplateInfobox Muslim scholars --> ( Persian /ابو علی الحسین ابن عبدالله ابن سینا (born Uroscopy is the historic medical practice of visually examining a patient's Urine for Pus, Blood, or other symptoms of disease

Early studies of hCG had concluded that it was produced by the pituitary gland. In the 1930s, Georgeanna Jones discovered that hCG was produced not by the pituitary gland, but by the placenta. This discovery was important in relying on hCG as an early marker of pregnancy. ^[2] Selmar Aschheim and Bernhard Zondek introduced testing based on the presence of human chorionic gonadotropin (hCG) in 1928. Selmar Aschheim ( October 4, 1878 &ndash 1965 was a German Gynecologist who was a native of Berlin. Bernhard Zondek (1891-1966 was a reproductive Endocrinologist who developed the first reliable Pregnancy test in 1928 Human chorionic gonadotropin ( hCG) is a Glycoprotein Hormone produced in Pregnancy that is made by the Embryo soon after conception ^[3] In the Aschheim and Zondek test, an infantile female mouse was injected subcutaneously with urine of the person to be tested, and the mouse later was killed and dissected. A mouse (plural mice) is a small Animal that belongs to one Presence of ovulation indicated that the urine contained hCG and meant that the person was pregnant. Note This article deals primarily with Human ovulation nonhuman Animal ovulation is touched on briefly at the conclusion A similar test was developed using immature rabbits. The rabbit test was an early Pregnancy test developed in 1927 by Bernhard Zondek and Selmar Aschheim. Here, too, killing the animal to check her ovaries was necessary. An improvement arrived with the frog test, which still was used in the 1950s and allowed the frog to remain alive and be used repeatedly: a female frog was injected with serum or urine of the patient; if the frog produced eggs within the next 24 hours, the test was positive. This article is about the block cipher algorithm For the ultrafast laser pulse measurement technique see Frequency-resolved optical gating. In most Birds and Reptiles an egg ( Latin ovum) is the Zygote, resulting from Fertilization of the Ovum.

Direct measurement of antigens, such as hCG, was made possible with the invention of the radioimmunoassay in 1959,^[4]. An antigen (from antibody-generating) or immunogen is a substance that prompts the generation of Antibodies and can cause an immune response Radioimmunoassay (RIA is a Scientific method used to test Antigens (for example Hormone levels in the Blood) without the need to use a Radioimmunoassays require sophisticated apparatus and special radiation precautions and are expensive. In the 1970s, the discovery of monoclonal antibodies led to the development of the relatively simple and cheap immunoassays used in modern home pregnancy tests. Monoclonal antibodies ( mAb or moAb) are monospecific antibodies that are identical because they are produced by one type of immune cell An immunoassay is a Biochemical test that measures the Concentration of a substance in a biological liquid typically serum or Urine, using the

Modern tests

The test for pregnancy which can give the quickest result after fertilisation is a rosette inhibition assay for early pregnancy factor (EPF). Enzyme assays are Laboratory methods for measuring enzymatic activity Early pregnancy factor (EPF or early conception factor (ECF is a Protein associated with Mammalian Embryos shortly after fertilization EPF can be detected in blood within 48 hours of fertilization. Human fertilization is the union of a human egg and sperm, usually occurring in the Ampulla of the fallopian tube. ^[5] However, testing for EPF is expensive and time-consuming.

Most chemical tests for pregnancy look for the presence of the beta subunit of hCG or human chorionic gonadotropin in the blood or urine. Human chorionic gonadotropin ( hCG) is a Glycoprotein Hormone produced in Pregnancy that is made by the Embryo soon after conception hCG can be detected in urine or blood after implantation, which occurs six to twelve days after fertilization. ^[6] Quantitative blood (serum beta) tests can detect hCG levels as low as 1 mIU/mL, while urine tests have published detection thresholds of 20 mIU/mL to 100 mIU/mL, depending on the brand. ^[7] Qualitative blood tests generally have a threshold of 25 mIU/mL, and so are less sensitive than some available home pregnancy tests. Most home pregnancy tests are based on lateral-flow technology. Lateral flow tests also known as Lateral Flow Immunochromatographic Assays are a simple device intended to detect the presence (or absence of a target analyte in sample (matrix

With obstetric ultrasonography the gestational sac sometimes can be visualized as early as four and a half weeks of gestation (approximately two and a half weeks after ovulation) and the yolk sac at about five weeks' gestation. Obstetric sonography (ultrasonography is the application of Medical ultrasonography to Obstetrics, in which ultrasound is used to visualize the Embryo The gestational sac (or gestation sac) is the only available intrauterine structure that can be used to determine if an intrauterine Pregnancy (IUP exists Gestational age is usually considered to be the age of an Embryo or Fetus (or newborn infant from the first day of the woman's last menstrual period (LMP The yolk sac is the first element seen in the Gestational sac during Pregnancy, usually at 5 weeks Gestation. The embryo can be observed and measured by about five and a half weeks. An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular The heartbeat may be seen as early as six weeks, and is usually visible by seven weeks' gestation. ^[8][9]

Accuracy

A systematic review published in 1998 showed that home pregnancy test kits, when used by experienced technicians, are almost as accurate as professional laboratory testing (97. 4%). When used by consumers, however, the accuracy fell to 75%: the review authors noted that many users misunderstood or failed to follow the instructions included in the kits. Improper usage may cause both false negatives and false positives. ^[10]

Timing of test

False negative readings can occur when testing is done too early. In Statistics, the terms Type I error (also α error, or false positive) and type II error ( β error, or a false negative Quantitative blood tests and the most sensitive urine tests usually detect hCG shortly after implantation, which can occur anywhere from 6 to 12 days after ovulation. Note This article deals primarily with Human ovulation nonhuman Animal ovulation is touched on briefly at the conclusion ^[6] Less sensitive urine tests and qualitative blood tests may not detect pregnancy until three or four days after implantation. Menstruation occurs on average 14 days after ovulation, so the likelihood of a false negative is low once a menstrual period is late. See also "Mensuration" a term sometimes used to describe Measurement, particularly in the context of Forestry.

Ovulation may not occur at a predictable time in the menstrual cycle, however. The menstrual cycle is a recurring cycle of physiologic changes that occurs in reproductive-age Females Overt menstruation (where there is blood flow from the A number of factors may cause an unexpectedly early or late ovulation, even for women with a history of regular menstrual cycles. Using ovulation predictor kits (OPKs), or charting the fertility signs of cervical mucus or basal body temperature give a more accurate idea of when to test than day-counting alone. Fertility awareness (FA refers to a set of practices used to determine the fertile and infertile phases of a woman's Menstrual cycle. The cervix (from Latin "neck" is the lower narrow portion of the Uterus where it joins with the top end of the Vagina. Basal body temperature is the body temperature measured immediately after awakening and before any physical activity has been undertaken

The accuracy of a pregnancy test is most closely related to the day of ovulation, not of the act of intercourse or insemination that caused the pregnancy. It is normal for sperm to live up to five days^[11] in the fallopian tubes, waiting for ovulation to occur. ^[12] It could take up to twelve further days for implantation to occur, meaning even the most sensitive pregnancy tests may give false negatives up to seventeen days after the act that caused the pregnancy. Because some home pregnancy tests have high hCG detection thresholds (up to 100 mIU/mL), it may take an additional three or four days for hCG to rise to levels detectable by these tests — meaning false negatives may occur up to three weeks after the act of intercourse or insemination that causes pregnancy.

False positives

False positive test results may occur for several reasons. In Statistics, the terms Type I error (also α error, or false positive) and type II error ( β error, or a false negative These include: errors of test application, use of drugs containing the assay molecule, and non-pregnant production of the assay molecule.

Spurious evaporation lines may appear on many home pregnancy tests if read after the suggested 3–5 minute window or reaction time, independent of an actual pregnancy. False positives may also appear on tests used past their expiration date.

A woman who has been given an hCG injection as part of infertility treatment will test positive on pregnancy tests that assay hCG, regardless of her actual pregnancy status. Female infertility|Male infertility Infertility primarily refers to the biological inability of a Man or a Woman to contribute to conception. However, some infertility drugs (e. g. , clomid) do not contain the hCG hormone. Clomifene ( INN) or clomiphene ( USAN and former BAN) or Clomid or Clomifert is a Selective estrogen receptor modulator (SERM ^[13]

Some diseases of the liver, cancers, and other medical conditions may produce elevated hCG and thus cause a false positive pregnancy test. The liver is a vital organ in the human body and is present in Vertebrates and some other animals Cancer (medical term Malignant Neoplasm) is a class of Diseases in which a group of cells display uncontrolled These include choriocarcinoma and other germ cell tumors, IgA deficiencies, heterophile antibodies, enterocystoplasties, gestational trophoblastic diseases (GTD), and gestational trophoblastic neoplasms (GTN). Choriocarcinoma is a malignant and aggressive Cancer, usually of the Placenta. A germ cell tumor ( GCT) is a Neoplasm derived from Germ cells Germ cells normally occur inside the gonads ( Ovary and Testis) Selective immunoglobulin A (IgA deficiency is a relatively mild genetic Immunodeficiency. Heterophile is an alternate term to heterosexual and once competed with it for currency but only did so successfully in Scandinavia Gestational trophoblastic disease is any type of abnormal proliferation of Trophoblasts during Pregnancy. (See Human chorionic gonadotropin. Human chorionic gonadotropin ( hCG) is a Glycoprotein Hormone produced in Pregnancy that is made by the Embryo soon after conception )

Viability

Pregnancy tests may be used to determine the viability of a pregnancy. Serial quantitative blood tests may be done, usually 2–3 days apart. Below an hCG level of 1,200 mIU/ml the hCG usually doubles every 48–72 hours, though a rise of 50–60% is still considered normal. Between 1,200 and 6,000 mIU/ml serum the hCG usually takes 72–96 hours to double, and above 6,000 mIU/ml, the hCG often takes more than four days to double. Failure to increase normally may indicate an increased risk of miscarriage or a possible ectopic pregnancy. Miscarriage or spontaneous abortion is the natural or spontaneous end of a Pregnancy at a stage where the embryo or fetus is incapable of surviving generally defined An ectopic pregnancy is a Complication of pregnancy in which the fertilized Ovum is implanted in any tissue other than the uterine wall

Ultrasound is also a common tool for determining viability. Obstetric sonography (ultrasonography is the application of Medical ultrasonography to Obstetrics, in which ultrasound is used to visualize the Embryo A lower than expected heart rate or missed development milestones may indicate a problem with the pregnancy. ^[9] Diagnosis should not be made from a single ultrasound, however. Inaccurate estimations of fetal age and inaccuracies inherent in ultrasonic examination may cause a scan to be interpreted negatively. If results from the first ultrasound scan indicate a problem, repeating the scan 7–10 days later is reasonable practice. ^[8]

References

1. ^ Clark, Stephanie Brown. (2005). Jan Steen: The Doctor's Visit. Literature, Arts, and Medicine Database. Retrieved 2007-05-27. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 927 - Simeon the Great, Tsar of Bulgaria, dies 1120 - Richard III of Capua is anointed
   Lubsen-Brandsma, M. A. (1997). Jan Steen's fire pot; pregnancy test or gynecological therapeutic method in the 17th century?. Ned Tijdschr Geneeskd, 141(51), 2513–7. Retrieved 2006-05-24. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1218 - The Fifth Crusade leaves Acre for Egypt. 1276 - Magnus Ladulås is crowned
   "The Doctor's Visit. " (n. d. ). The Web Gallery of Art. Retrieved 2006-05-24. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1218 - The Fifth Crusade leaves Acre for Egypt. 1276 - Magnus Ladulås is crowned
2. ^ Damewood, Marian D. ; John A. Rock (August 2005). "In memoriam: Georgeanna Seegar Jones, M.D.: her legacy lives on". Fertility and Sterility 84 (2): 541-2. American Society for Reproductive Medicine.  
3. ^ Speert, Harold (1973). Iconographia Gyniatrica. Philadelphia: F. A. Davis. ISBN 978-0803680708.  
4. ^ Yalow, RS; SA Berson (July 1960). "Immunoassay of endogenous plasma insulin in man". Journal of Clinical Investigation 69: 1157-75. PMID 13846364.  
5. ^ Fan XG, Zheng ZQ (1997). "A study of early pregnancy factor activity in preimplantation". Am. J. Reprod. Immunol. 37 (5): 359-64. PMID 9196793.  
6. ^ ^{a b} Wilcox AJ, Baird DD, Weinberg CR (1999). "Time of implantation of the conceptus and loss of pregnancy. ". New England Journal of Medicine 340 (23): 1796–1799. doi:10.1056/NEJM199906103402304. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. PMID 10362823.  
7. ^ Waddell, Rebecca Smith (2006). FertilityPlus.org. Home Pregnancy Test hCG Levels and FAQ. Retrieved on 2006-06-17. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1462 - Vlad III the Impaler attempts to assassinate Mehmed II ( The Night Attack) forcing him to retreat
8. ^ ^{a b} Woo, Joseph (2006). Why and when is Ultrasound used in Pregnancy?. Obstetric Ultrasound: A Comprehensive Guide. Retrieved on 2007-05-27. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 927 - Simeon the Great, Tsar of Bulgaria, dies 1120 - Richard III of Capua is anointed
9. ^ ^{a b} Boschert, Sherry (2001-06-15). Year 2001 ( MMI) was a Common year starting on Monday according to the Gregorian calendar. Events 763 BC - Assyrians record a Solar eclipse that will be used to fix the Chronology of Mesopotamian history "Anxious Patients Often Want Very Early Ultrasound Exam". OB/GYN News. FindArticles. com.  
10. ^ Bastian LA, Nanda K, Hasselblad V, Simel DL (1998). "Diagnostic efficiency of home pregnancy test kits. A meta-analysis". Arch Fam Med 7 (5): 465–9. PMID 9755740.  
11. ^ Weschler, Toni (2002). Taking Charge of Your Fertility, Revised Edition, New York: HarperCollins, p. 374. ISBN 0-06-093764-5.  
12. ^ Ellington, Joanna (2004). Sperm Transport to the Fallopian Tubes. Frequently Asked Questions with Dr. E. INGfertility Inc. Retrieved on 2006-08-13. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 3114 BC - According to the Lounsbury correlation the start of the Maya calendar.
13. ^ Phillips, Pat (2007). Early Pregnancy Tests. Pregnancy Test FAQ. Retrieved on 2007-03-04. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 51 - Nero, later to become Roman Emperor, is given the title Princeps iuventutis (head of the youth